This invention relates to a heat treating furnace of the type in which electric resistance heating elements are disposed inside of a work chamber to radiantly heat workpieces therein. More specifically, the invention relates to a furnace of the type in which the work chamber is of circular cross-section and in which the heating elements are made of rigid graphite bars.
In most prior furnaces of this type, the graphite heating bars are arranged in a circle around the chamber and extend longitudinally of the furnace between the front and rear thereof. As a result, it is not feasible to easily arrange the elements in groups or banks which may be differentially located and/or energized in order to establish front-to-rear temperature trim zones in the furnace.